Boyfriend confusion

Amarina
So for the last few weeks I feel like I've slightly lost interest in my boyfriend? We've been together a year and a half and when I'm with him I don't think about anyone else. I still absolutely love him and we even talk about getting married but I can't help but think about other guys sometimes. I'm so worried I'll lose all moral control and cheat on him. I know youre thinking "you wouldn't cheat on him if you really loved him" but I kinda just miss the excitement of a hookup and atm I feel like our relationship is so boring and I'm not sure I enjoy the sex anymore. Last night I went out to town with an old fwb and I really wanted to get with him but I knew it wasn't right. I've been thinking about it all day. I don't know if this is just a phase I'm so confused and conflicted as to what I want.